GOMA, Congo  Rebels in Congo believed to be backed by Rwanda postponed their departure Friday from the key eastern city of Goma by 48 hours for “logistical reasons,” defying for a second time an ultimatum set by neighboring African countries and backed by Western diplomats.

The delay raises the possibility that the M23 rebels don’t intend to leave the city they seized last week, giving credence to a United Nations Group of Experts report which argues that neighboring Rwanda is using the rebels as a proxy to annex territory in mineral-rich eastern Congo .

“We will be out of Goma on Sunday, and will go back to our initial positions in Kibumba,” M23 rebel spokesman Lt. Col. Vianney Kazarama said Friday, referring to a town 15 miles north of Goma.

The regional bloc representing the nations bordering Congo had issued a Friday deadline for the M23 fighters to retreat, after the rebels had thumbed their nose at an earlier ultimatum. Kazarama’s announcement suggests the rebels are dragging their feet.

In a sign of how confused the situation remained Friday morning, a barge carrying about 280 Congolese policemen arrived at Goma port, on the banks of Lake Kivu. The policemen had fled when the rebels took the city, and were returning to resume control of the city Friday, as had been earlier agreed.

The Congo government police appeared disoriented, unsure what to do and they did not disembark from the barge, as M23 fighters patrolled the port.